CHICAGO  Officials of a Catholic liberal arts college shut it down indefinitely Friday and told students to leave campus after threatening messages were found scrawled in the bathroom of a freshman dorm.

Graffiti were found twice this month at St. Xavier University's Regina Hall, including a message Thursday that read, "Be prepared to die on 4/14," President Judith Dwyer said in a statement.

Officials closed down campuses in Chicago and suburban Orland Park, along with classroom space in downtown Chicago, and canceled all classes for the school's 5,700 students. Buildings where community events are planned will remain open, Dwyer said.

"In this day and age, given Virginia Tech and Northern Illinois University, when you have a threat made against students or other members of the university community, you have to take steps to ensure that everyone is safe," university spokesman Joe Moore said Friday. "Even if that means erring on the side of being overly cautious."

Moore declined to give more details on the graffiti, citing the continuing investigation.

Security has been increased, including the use of Chicago police and the FBI, said Chicago police spokeswoman Monique Bond.

No one was in custody Friday evening. Students began leaving dorms Friday to meet a Saturday noon deadline for the closure, police said.

Graffiti were first found April 5 in a bathroom stall at the coed dorm. The message was of a "threatening but nonspecific nature," the school said in a statement.

It was reported to campus authorities and Chicago police. St. Xavier increased staff at the dorm, which houses about 245 students, and discussed the message with the people who lived there, officials said.

Then officials found the second message referencing the threat for Monday.

Many students have been interviewed, and the dorm hosted group discussions to reassure students, Moore said. The university will help students who cannot afford to travel home or who don't have a place to stay, he said.

Campuses around Illinois have been on alert since a Valentine's Day shooting when a gunman burst into a lecture hall at NIU, killing five students and wounding 18 others before turning the gun on himself.

The FBI's Joint Terrorism Task Force arrested a student at the University of Illinois at Chicago in late February on suspicion of making e-mail threats of a "mass shooting" on the UIC campus. She was charged with one count of making threats through use of interstate commerce.

And Illinois State University said in late February that police were investigating graffiti found in a dorm bathroom that referenced the NIU shooting. The message was scrawled in black marker on a toilet-paper dispenser and read, "ISU is the next NIU."

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